Wheel truing mechanism



Jan. 16, 1940. RfE. FLANDERS WHEEL TRUING MECHANISM Filed Jan. 29, 19376 Sheets-Sheet l J les 1/,

Jan. 16, 1940. R. E. FLANDERS WHEEL TRUING MECHANISM 6 Shets-Sheet 2'Filed Jan. 29, 1937 w Q 0 0 ../I \m m.

Jan; 16, 1940.

R. FLANDERS WHEEL TRUING MECHANISM Filed Jan. 29, 1937 6 Sheets-Sheet 3Jan. 16, 1940.

R. E. FLANDERS WHEEL TRUING MECHANISM Jan. 16, 1940. R. E. FLANDERSWHEEL TRUING MECHANISM Filed Jan. 29, 1937 6 Sheets-Sheet 5 device.

Patented Jan. 16, 1940 PATENT OFFICE wnnnr. TBUING MECHANISM mum} E.Flanders, Springfield, Vt., assignor to Jones & Lamson Machine Company,Springfield, Vt., a corporation of Vermont Application January 29, 1937,Serial No. 122,971

' 17 Claims.

This invention relates to mechanism for truing grinding wheels, and hasfor a particular object to provide a simple mounting and actuating meansapplicable to a plurality of truing tools by which high accuracy ofwheel contour may be produced and maintained, and by which contourswhich may differ widely from each other may be produced by effectingminor changes and substitutions in the mechanism.

A further object is to provide for truing traverses in a manner whichwill maintain a true wheel contour regardless of the helical angle ofthe wheel and without danger of chipping the wheel edge.

To these ends each truing tool is carried by a rock arm so arranged thatas the arm is rocked,

the tool is caused to traverse a wheel face, and the position of the armlengthwise of the rocking axis is controlled to determine the contour ofthe face being traversed. In order to avoid danger of chipping oi thewheel edges, the tool may be arranged to true only on that stroke inwhich the contacts are first made with the wheel edges and progress awayfrom these edges.

This application is a continuation in part of my application SerialNumber 46,756 filed October 25, 1935, for Grinding machine.

For a more complete understanding of this invention, reference may behad to the accom- .30 panying drawings in which:

Figure 1 is a horizontal section through a tru ing mechanism embodyingthe invention, on line l--l of Figure 2.

Figure 2 is a vertical section on line 2--2 of Figure 1.

Figure 3 is a detail section on line 3-4 of Figure 2.

Figure 4 is a section on line 4-1 of Figures 1 and 2.

Figure 5 is an end elevation of the mechanism showing the truing tools.

Figures 6 and 7 are detail sections on line 6-8 and 1-'|, respectively,of Figure 1.

Figure 8 is a development of the traverse cam.

Figure 9 is a diagrammatic showing of the normal idle positions of threetruing devices with relation to the wheel edge for truing to UnitedStates standard thread contour.

Figures 10, 11, and 12 are views somewhat similar to Figures 1, 2 and 5,respectively, but arranged for truing the wheel to grind buttressthreads.

Figure 13 is a detail section on line ll-l2 of Figure 11 showing thecontrol for the top truing Figure 14 is a view similar to Figure 9, butshowing four truing devices arranged for truing the wheel for buttressthreads, and where the wheel operates close to a shoulder on the work.

Figure 15 is a vertical cross section somewhat 5 similar to Figure 1,but showing a modified construction.

Figure 16 is a section on line Iii-l6 of Figure 15.

; Figure 17 is a section on line l|-Il of Figure 10 16.

Figures 18 and 19 are detail sections on lines Iii-J8 and |9--i9,respectively, of Figure 17.

Figure 20 is a view somewhat similar to Figure 15, but showing a furthermodification particu- 16 larly designed to true a wheel to a specialcontour.

Figure 21 is a detail section on line 21-2l of Figure 20.

Figure 22 is a detail section on line 22-22 of 0 Figure 21.

Figure 23 is a detail section on line 2323 of Figure 20.

Figure 24 is a fragmentary section through the mechanism on line 24-4-24of Figure 20.

Figure 25 is a detail section on line 25-25 of Figure 24.

Figure 26 is a detail section on line 26- 26 of Figure 21.

Figure 27 is a plan view of a pair of cam ele- 30 ments for controllingthe truing devices to true a grinding wheel to the contour shown inFigure 28;

Figure 28 is a detail section showing the contour of wheel and workproduced when the earns 85 of Figure 27 are used.

Figure 29 is a view similar to Figure 28, but showing the wheel and workcontours produced by employing came shown in Figure 20.

Figures 30 to 32 are views similar to Figures 2.8 40 and 29, but showingother possible contours which can be produced by using suitably shapedcontrolling cams.

Wheel truing mechanism, United States 45 standard threads Referringfirst to the construction shown in Figures 1 to 5, the mechanism thereinillustrated is designed to true the wheel to the shape for rindingUnited States standard threads. 50

The mechanism as shown is housed within a casing 50, the forward end ofwhich is formed cylindrical, as at SI, and projects toward the grindingwheel I and is suitably mounted on the wheel slide (not shown) withcapacity for axial movement thereon from and toward the wheel. As thismounting and moving mechanism forms no part of the present invention, itis not herein illustrated.

As shown best in Figures, 1 and 2, the casing 5I is provided with aforward wall portion 60 having a reentrant central portion at 6| andinclined side wall portions 62. Through these wall portions 62 arearranged bearing sleeves 63, which are arranged between packing rings 64and 65 enclosing between them packing 66 to prevent the passage of metalparticles, abrading material, and coolant through these wall members andinto contact with the mechanism housed within the casing 5|. Journaledin each of the sleeves 63 is a shaft I0, which has clamped thereto anarm II carrying a diamond truing'tool I2 at its end, eccentric to itsshaft 10. By maintaining the casing 50 full ofoil, the seepage of thisoil out around the shafts I acts as a further aid in preventing theentry of grit and other foreign matter into this casing. The two shaftsI0 are arranged at angles of 120 to each other so that the two diamondsI2, when the corresponding shaft I0 is rocked, are caused to traversethe inclined side faces I of the grinding wheel I. These inclined sidefaces of the grinding wheel define the shape of the threads and thevalleys,

between them in the work being ground. One of these diamonds I2, ispositioned slightly above the other, as shown in Figure 9. They arerocked to effect such traverse of the wheel faces by a cam drum I6,which has a pair of cam grooves 11 therein, each of these groovescooperating with followers I9 on the ends of bars 18. The forward endsof these bars are clamped to the shafts I0 so that as the rear ends ofthe arms I8 are moved up and down by engagement of their cam followersin the grooves Il, these shafts I0 are rocked.

In order to provide for extreme accuracy in setting, means are providedfor slightly varying the angles of traverse of the diamonds across thewheel face. To this end, means are provided by which, beside the rockingmotions of the shafts I0 produced by the rocking action of the bars 18,they may be given a slight axial motion simultaneously therewith. Asshown this is done by prolonging the bars I8 forwardly of the shafts I0and providing on the prolonged end of each, as at 90, a cam follower 9I,which rides on a cam plate 92. This cam plate 92 is adjustably supportedat either end (see Figure 7) on the adjusting screws" 93 and 94 threadedthrough the inclined casing wall 62. By adjusting the plate 92angularly, the forward end of the corresponding lever arm I8 may begiven a motion axially of the corresponding shaft I0, moving the shafttherewith, thus to efiect an axial movement of the shaft at the sametime that it is rocked. The amount of this axial movement depends on therelative adjustment of the two screws 93 and 94, and it may be made inopposite directions for the same direction of rocking of thecorresponding shaft 10, by tilting the plate 92 in one or the otherdirection from parallelism with the wall member 62. By this means a veryaccurate control of the inclined wall contour of the grinding wheel ismade possible. The cam drum I6 is journaled on a vertical shaft 96, andis arranged to be rocked in opposite directions by the rotation inopposite directions of a worm 91 engaging worm teeth 98 in a portion ofthe periphery of the cam 15. This worm 9'! is driven through frictionplates, shown generally at 99, from a shaft I00, this friction drivebeing interposed in order that there may be a full traverse of thediamond points, but without danger of overthrow, the shaft I00 beingrotated through a sufficient angular distance to insure the rocking ofthe diamond points throughout their entire permissible amplitude, anyfurther turning of the shaft I00 being taken up in slippage in thefrictional connection.

It is also desirable that the diamonds be moved in'contact with thegrinding wheel only in a direction away from the apex of the wheel andthus inwardly from the wheel periphery, as if it be attempted to truein. the opposite direction, there is danger of chipping the wheel edge,To this end provision is made for relieving the diamonds from the wheelduring their rocking motion back toward the apex of the wheel. This isaccomplished by a rocking cam plate ml, which is journaled on a bushingI02 on the cam shaft 96. A pin I03 projects downwardly from the cam I6between a pair of shoulders I04 and I05 (see Figures 1, 2 and 3) in thecam plate IOI.

A second pin I06 secured in the base of the hous-.

ing 50 projects between a pair of shoulders I01 and I08 on the cam plateIOI. This cam plate also has oppositely disposed notches I09 having longinclined faces IIO against which ride abutment screws III carried at therear ends of a pair of arms II2, the forward ends of which are fulcrumedas at II3 on the base of the casing 50. Projecting down from each of thearms 18 is a pin H4 which engages in a notch H5 in the arm II2 beneathit. During the rocking movement of the cam I6 in a direction to traversethe diamonds from the point rearwardly across the faces of the grindingwheel, the pin I03 rides from the position shown in Figure 3 in fulllines to the dotted line position, whereupon further turning of the camI6 causes a rocking of the cam plate IOI in a direction to cause theinclined faces I I0 to ride out against the abutments III, thus to swingthe rear ends of the arms. II2 outwardly, which, acting through the pins4, causes the rock shafts to be moved axially in a direction to retractthe diamond points from their normal truing positions. The arms II2remain in this position during the reverse rocking motion of the cam I6until the pin I03 engages the shoulder I05 and starts to turn the camplate IOI in the reverse direction to the position shown in Figure 3,whereupon a spring I20 (Figure 1) seated in a socket in the rear end ofeach of the shafts I0 and bearing on a pin I2I projecting into thissocket from the base of the cupshaped member I22 carried by the casing50, and in which the rear end of each of the shafts I0 rides, returnsthe shafts I0 to their normal operative positions, and returns theabutments III into the notches I09 in the position shown in Figure 3.,The shoulders I01 and I08 act with the pin 106 as stops to limit theextent of rocking motion of the cam plate IOI.

Beside the two diamonds I2 which true the inclined faces of the wheel, athird diamond I30 is shown to true on? the apex of the wheel in order toconform to United'States standard threads.

This diamond is shown as positioned slightly above the horizontal planeof the grinding wheel shaft IOI (Figures 2 and 9) and it is carried by arock shaft I3I (see Figure 2), being mounted in a holder I32 similar tothe holders for the side face truing diamonds I2. The shaft I3I ismounted in a packed bearing I33 and back of this bearing it has clampedthereon, a collar I35 having a pair of cam rollers I36 journaled onstuds projecting therefrom. These cam rollers ride on a peripheral camridge I31 on the upper face of the cam 16 (Figures 2 and 4), so that asthe cam 16 is rocked, the shaft I3I is rocked to cause the diamond I30to pass across the apex of the wheel. This rock shaft I3I is pressedforwardly toward the wheel I, as by a spring I40 seated in a socket l4l,and reacting against a plug I42 which bears at its outer end against akey pin I43 extending through oppositely disposed slots I44 of the rockshaft I3I., Against the opposite face of this key pin I43, is a secondplug I 45 against which may bear the threaded extremity I46 of amicrometer adjusting screw I41. The spring I40 holds the inner end ofthe screw I41 against the pin I43, and by adjusting the screw I41, thelimit of inward axial position of the shaft I3I may be adjusted todetermine the amount of the apex of the wheel which will be removed bythe diamond I30. In operation the truing mechanism as a whole is firstmoved toward the wheel edge into truing position. Then the shaft I00 iscaused to turn first in one direction and then in the other sufficientlyto rock the cam drum 16 in one direction and then in the other betweenits limits of motion, any excess in the rotation of the shaft I00 beingtaken up in the slippage of the slip drive 99. Rocking of the cam drumin the first direction rocks the side truing devices backwardly from theapex of the grinding wheel across its inclined side faces and the endtruing device I30 across the apex of the wheel between these side faces.As the cam drum is about to reach its rocking limit in this direction,it rocks the cam plate IOI which retracts the side truing devicesthrough axial motions of their carrying rock shafts so that during thereverse motion of the cam drum they are returned to their initialposition out of contact with the wheel, the last portion of this motionbeing again effective on the cam plate IM to return the side truingdevices to their operative positions axially of their rock shafts. Thecam drum then stops with the parts again in position for the start ofthe truing cycle.

A modified construction of a truing mechanism designed to United Statesstandard thread contour is illustrated in Figures 15 to 19. In thesefigures the truing mechanism is contained within a cylindrical casingI50 which carries'a motor I5I by which the truing mechanism is actuated.This motor I5I drives, througha coupling I52, a shaft I53 joumaled inspaced partition members I54 and I55. Between these partition membersthe shaft I53 carries a worm I56 which meshes with a worm wheel I51 on atransverse shaft I58. This shaft, in turn, carries a worm I59 whichmeshes with a worm wheel I60 on a cam shaft I 6|. The forward endportion of this cam shaft carries an actuating cam I62 having a camgroove I63 therein. In this cam groove rides a cam follower roll I64carried by an arm I65 which is secured to a rock shaft I66.

Also secured to this rock shaft is a second shorter arm I61. The arm I65has a bifurcated portion I60, the forks of which ride in notched sideportions I10 of a circular rack bar "I, so that as the arm I65 is rockedthis rack bar I1I' is given an axial motion. The arm I61 is likewiseprovided with a bifurcated portionv which rides in similar recesses inthe sides of a rack bar I15. These rack bars are mounted in suitableframe portions of the casing I50, and, as shown, are parallel to eachother and to the axis of the casing. The teeth on these rack bars arearranged at an angle to the perpendicular to their respectivelongitudinal 'axes and in a direction to engage with the teeth ofsegmental pieces as I16 (see Figure 19) secured to the rock shafts I11which are arranged at angles of 120 to each other, and carry at theirouter ends outside of the casing I50, the side truing tools, such asI80, which may be constructed and mounted similarly to the correspondingparts shown in Figures 1 to 9. l

The axial positions of these rock shafts I11 may be controlled by cammeans somewhat similar to that shown in Figure 7 and illustrated moreparticularly in Figures 1'1 and 19. Referring to these Figures, it willbe noted that each segment I16 has a lateral extension I82 carrying afollower I83, whicn, as the corresponding shaft I11 is rocked, movesalong and in contact with a cam plate I85. This cam plate may beangularly adjusted with reference to a cross frame member I86 of thecasing I50, as by means of the individually adjustable threaded plugsI81 and I88 which bear in recesses in the cam plate I85. The

cam I62, therefore, controls the motion of bothof. the side truingdiamonds which are moved simultaneously backward and forwards.

The third truing device shown at I90 which trues off the apex'of thegrinding wheel I is shown as carried by a rock shaft I9I to which issecured an actuating arm I92. This arm has its end portion I93positioned to be actuated by a peripheral cam portion of the cam I62,this cam I62 having a flattened portion I94 (see Figure 16) whichpermits the arm I92 to be rocked inwardly by the action of a spring I95and then forces the arm I92 outwardly to produce a double stroke of thedressing diamond I90 during one portion of the rotation of the cam I62.

The axial position of the shaft I9I may be cam-controlled as are theaxial positions of the rock shafts I11, and for this purpose it isshownas provided with a bearing boss I96 which rides against an adjustablescrew abutment I91 (see Figure 15). The portion I96 is held against thisabutment as by means of a coil spring I98 which surrounds a reduceddiameter extension portion of the shaft I9I, the extreme end of which isjournaled in the partition member I and is shown in alinement with theshaft I53.

No provision is made in this construction for the retraction of theindividual tools by axial motion of their respective rock shafts on thereturn traverse of the side truing tool, but the same result may beaccomplished by, effecting a retraction of the entire mechanismduringthe return traverse of the side truing devicesso that truing iseffected only during their direction of motion backwardly from the apexof the wheel. It will be noted that the cam I'62 is so designed that ona single complete'revolution, it' effects both the active traverse andthe idle traverse, the arm" I65 being returned quickly by a relativelysteep portion of the cam path I63. As

tion of the cam [62, and this is all done while the mechanism is intruing position, the top truing device being idle during the time themechanism is retracted from truing position.

.The particular manner in which this retraction of the entire mechanismis produced, per se, forms no part of the present invention and hastherefore not been shown herein.

Wheel truing mechanism for buttress threads In Figures 10 to 14 is showna modification of the truing mechanism of the general type of Figures 1to 9 intended for grinding buttress threads and where the threads extendso close to a shoulder on the work that one face of the grinding wheelmust be trued off to permit the grinding wheel to work up suflicientlyclose to the shoulder. The side face dressing diamonds with thismechanism are arranged in the angularrelationship shown in Figure 10.Other than this changed angular relationship, the mounting and actuationof the side diamonds from the rocking cam are the same as that for theUnited States standard threads as previously described in connectionwith Figures 1 to 9.

The rock shaft l3la, which carries the apex truing diamond I 30a, hassecured thereto a cam arm 200 having a roller 20! riding on the top ofthe cam 13a, which is provided with acam indentation 160' into and outof which the cam follower 20| rides in order to impart the desiredrocking motion to the shaft l3la when the cam 16a is rocked. The shaft131a otherwise may be mounted similarly to the shaft [3| shown in Figure2.

Afourth diamond 205 for dressing out one side of the grinding wheel isemployed in this construction. This diamond 205 is carried by a verticalrock shaft 206 (Figures 10, 12 and 13). This ,rock shaft 206 is suitablyjournaled in upper and lower spaced bearings 20'! and 203 and justbeneath the bearing 201, this shaft 206 has fixed thereto an arm 209,which has a head 2l0 (see Figure 13) riding in a slot 2 in the end of ahorizontal bar 2l2 which is slidable axially in a pair of bearings 2l3and 2. The top of the rocking actuating cam 16a is provided with anupwardly extending pin 2| 5, which engages a collar 2l'6 on the bar'2l2and this collar 2H5 is held in contact with the -pin 2l5 by the coilspring 2| 1 surrounding the bar 212 and bearing at one end against thebearing 2| 4 and at the other against the collar 2l6. Rocking of the cam16a thus moves the bar 2 l2 axially and rocks the shaft 206 and thediamond 205.

The fourth truing diamond in its motion hollows out the side face of thegrinding wheel as at 2| 8 substantially parallel to the plane of maximumwheeldiameter (shown in Figure 14'), so that the grinding wheel isenabled to work up to threads close to a shoulder on the work.

Wheel truing mechanism for special shapes of threads In the mechanismspreviously described, the axial motion of the rock shafts which carrythe side truing tools has been controlled for the purpose of correctingfor slight inaccuracies of wheel contour which might otherwise beproduced, but it is quite possible to employ this axial motion of therock shafts more extensively in order to provide for various wheelcontours of special or unusual shapes. Mechanism in which thiscapability is utilized is shown in Figures 20 to 27 and various spacedwheel contours and resuiting contours of work are illustrated in Figures28 to 32, inclusive.

The mechanism shown in Figures 20 to 27 is of the general typeillustrated in Figures 15 to 19 wherein the idle traverse of the sidetruing tools is produced by the retraction of the entire truingmechanism, motions of the truing tools being produced by the rotationrather than by the rocking of an actuating cam and the mechanism beingretracted and there held during one portion of the angular motion of theactuating cam while the tools are being retracted toward the wheel apex.

At 300 in Figure 24 is shown the motor for actuating the truing tools,this motor being connected through a reduction gear mechanism comprisinga worm 30! on the motor shaft 302, a worm wheel 303 on a transverseshaft 304, and a worm 335 on this transverse shaft meshing with a wormwheel 306 on a shaft 301. This shaft 301 extends rearwardly in thecasing and controls the retracting mechanism as previously mentioned andas shown in my patent application Serial No. 94,903, heretoforementioned. The shaft 304, also, drives, through the same worm 305, aworm wheel 3"] of the same size as the worm wheel 306, but secured to acam shaft 3 positioned substantially at right angles to the shaft 301.This shaft 3H which is journaled in the bearing posts 3H2 and 3E3carries the cam 3M which actuates the side truing devices, no apextruing device being employed in this mechanism, the side truing devicescontrolling the complete contour of the grinding face of the wheel beingtrued. The truing devices are carried by the angularly related rockshafts 320 which may be pressed forwardly, as by the springs 322 seatedin recesses in their rear ends and reacting against abutment plugs 324,substantially as illustrated in the previously described truingmechanisms.

To each of these rock shafts 320 is secured an arm 330, both ofwhich'are rocked by an actuating mechanism, the connections being suchas to permit axial motion of the rock shafts 320 as they are beingrocked. This actuating mechanism comprises a somewhat T-shaped rockmember 33I journaled on a stub shaft 332 and having at the extremity ofthe central arm a cam follower 333 which rides in a cam groove 334 inthe cam 3, so that as the cam 3| 4 is rotated the rocker 33l is rockedfrom side to side. The other arms of the rocker 33!, and the arms 330secured to the truing device rock shafts, are provided with groove 335and rollers 336 riding in these grooves so that the rocking of therocker 33! will rock the arms 330 and yet will permit them to be movedaxially. As shown the rollers 336 are carried by the arms 330, and thegrooves 335 are formed in the rocker 33 l, these grooves being arrangedangularly to the rock axis of this rocking member and substantiallyparallel to the axes of the rock shafts 320.

The axial motions of the rock shafts 320 are controlled by a pair ofedge cams 340. As shown in Figures 23 and 27, these edge cams are formedas plates which may be secured, as by a pair of screws for each at 34 I,to a supporting block 342. Each of these blocis may have a dovetailsliding connection with' a supporting yoke 345 and the axial position ofthe blocks 342 with respect to opposite arms of this yoke support may beadjusted, as by means of the oppositely disposed the adjustable camfollowers 350. Each of these followers is mounted at the outer end of alever which is fulcrumed as by the pin 352 to a block 353 secured to oneof the rock shafts such as 320. As shown the block 353 is positionedbetween a collar 354 pinned to the rock shaft 326 and a spacing sleeve355 which abuts at its forward end against a head 356 of the rock shaft,

this sleeve 355 being keyed to the rock shaft and rocking in a bearingbushing 351 in the forward wall 358 of the main casing.

The collar 354 and the block 353 are held for simultaneous rockingmotion, as by means of a pin 359 in'the collar 354, which extends into arecess 360 in the block 353. A short arm 365 of the lever 35| is shownas provided with a hearing roll 366 which engages the end of a hardenedabutment pin 361 carried by the casing wall 358. With this arrangementthe roll 366 is held against the abutment pin 361 and the follower 350is held against the edge of the cam plate 340 by the correspondingspring 322 so that as the rock shaft is rocked and the follower 350passes along the cam edge of the corresponding cam plate, the axialposition of the truing-device-carrying-rockshaft is determined by thecam contour. Various types of wheel contour may be accurately producedby employing correspondingly shaped controlling cams. For example, withthe cam plates 340, shown in Figure 27, a wheel contour with acorresponding shape of threads in the work may be produced as shown inFigure 28, the wheel being indicated at la. In Figure 29 the contour ofthe wheel lb is that determined by the cam contour shown in Figure 20.By employing cams of other suitable shapes, wheel and work contours- A3,A4, A5 and B3, B4, B5, respectively as illustrated in Figures 30, 31 and32, for example, may be made. Figure 31 illustrates the fact that byemploying different shaped cams for the two truing device rock shafts,unsymmetrical contours may be produced, the control of the axialposition of each of the rock shafts which carries the truing diamondbeing quite independent of the control for the other.

In Figures 21 and 22, also, a desirable mounting for the truing diamondon its carrying shaft is illustrated. The head 356 of this shaft, asshown in Figure 22, may be provided at its outer end with a transversewedge shaped groove 310 and engaging in this groove may be acomplementally shaped part 3" of the block 312. This block 312 may befixed in position in engagement with the groove in the rock shaft head356, as by a screw 313 passing therethrough and threaded into the rockshaft at the base of the groove 316. This block 312, as shown in Figure21,: is provided with a hole 315 to receive the diamond truing element316 which may have threaded engagement at its rear end, as at 311, withthe block. It may be fixed in axially adjusted position in the block, asby means of the set screw 318.

This application is a continuation in part of my application Serial No.46,756, flied October 25*, 1935, for Grinding machine.

From the foregoing description of certain embodiments of this invention,it should be evident to those skilled in the art that various otherchanges and modifications may be made without departing from the spiritor scope of this invention as defined by the appended claims.

I claim:

1. Mechanism for truing a wheel comprising a rock arm, means supportingsaid am to rock on an axis substantially perpendicular to the face ofsaid wheel to be trued, a wheel truing device carried by said arm, meansfor rocking said arm, and means acting during the rocking of said arm tomove said arm lengthwise of its rocking axis.

2. A wheel truing mechanism comprising a rockable andaxially movableshaft, an arm on said shaft, a wheel truing device on said arm, meansfor rocking said arm to thereby cause said device to traverse a grindingwheel face, and means actuable to move said shaft axially to bring saiddevice out of contact with said wheel for one direction of rocking ofsaid shaft.

3. A wheel truing mechanism comprising a plurality of rockable andaxially movable shafts, an arm on each shaft, a wheel-truing devicecarried by each arm, a lever rockable with each shaft, a rockingactuating cam cooperating with said lever, and means for rocking saidcam.

4. A wheel truing mechanism comprising a plurality of rockable andaxially movable shafts, an arm on each shaft, a wheel-truing devicecarried by each arm, a lever rockable with each shaft, a rockingactuating cam cooperating with said lever, means acting near the limitof rocking of said shafts in opposite directions to move said shaftsaxially in one and then in the opposite direction to move said devicesinto and out of operative relation to said wheel.

5. A wheel truing mechanism comprising a plurality of rockable andaxially movable shafts, an arm on each shaft, a wheel-truing devicecarried by each arm, a lever rockable with each shaft, a rocking camcooperating with said lever, means for rocking said cam, and adjustablemeans cooperating with said lever during its rocking motion to controlthe operative axial positions of said shafts whereby adjustment ofangular relation of the trued faces of the grinding wheel may beeffected.

6. A wheel truing mechanism comprising a plurality of rockable andaxially movable shafts, an arm on each shaft, 2. wheel-truing devicecarried by each arm, a lever rockable with each means for rocking saidcam, an angularly adjustable cam plate, a follower on said lever ridingon said cam plate to thereby determine the axial position of said shaftduring operative traverse of said device on said wheel, and spring meansfor holding said follower against said plate.

7. Wheel truing mechanism comprising a plurality of truing devices,means for traversing said devices across angularly related faces of thegrinding wheel in arcuate paths substantially parallel with therespective faces, and means adjustable to produce motion of said devicesaxially 01' said arcuate paths while said devices are in contact withthe wheel to vary the effective paths of said devices and thereby theangular relationship of the trued faces of said wheel.

8. A wheel truing mechanism comprising a plurality of rockable andaxially movable shafts, an arm on each shaft, a wheel truing devicecarshaft, a rocking cam cooperating with said lever,

provided with an interposed slip clutch for traversing said tool acrossa wheel face, and means for positively stopping the stroke of said toolat a predetermined point whereupon said slip clutch may becomeeffective.

10. A wheel truing mechanism, comprising a rock shaft, an arm, a truingdevice carried by said arm, a gear segment carried by said shaft, a rackbar having teeth meshing with the teeth of said segment, means formoving saidrack bar to rock said shaft, and means for moving said shaftaxially as it is being rocked.

11. In a wheel truing mechanism fora wheel having angular relatedgrinding faces, a pair of rock shafts arranged substantiallyperpendicular to said faces, an arm carried by each rock shaft,

-a truing device carried by each arm, means for rocking such shaftscomprising a pair of rack bars arranged in substantially parallelrelation and each at an angle to its respective shaft, the

teeth of each rack bar being arranged at an angle thereto, segmentscarried by each rock shaft meshing with the teeth of its bar, a cam,operative connections from said cam for moving said rackbars axially,and means for actuating said cam.

12 A wheel truing mechanism, comprising a pair of rock shafts, an armcarried by each .rock shaft, a truing tool carried by each arm, anactuating arm carried by each shaft, a rock member, operativeconnections between said rock member and arms, means for rocking saidrock member,

and means for moving said shafts axially while they are being rocked;

13. A wheel truing mechanism, comprising a rock shaft, an arm carried bysaid rock shaft, a truing tool carried by said arm eccentric to saidshaft, means for rockingsaid shaft, a lever fulcrumed to said shafttransverse to its axis, and means engaging said lever and acting to movesaid shaft axially as it is being rocked.

14. A wheel truing mechanism, comprising a rock shaft, an arm carried bysaid rock shaft, a truing tool carried by said arm eccentric to saidshaft, means for rocking said shaft, a spring tending to hold said shaftin one axial position, an arm carried by said shaft to swing through anare as said shaft is rocked, and a cam with which said arm engages andagainst which said arm is pressed by said spring for moving said shaftaxially against the pressure of said spring during the desired rockingmotion of said shaft.

15. A wheel truing mechanism, comprising a rock shaft mounted forrocking and axial motion, a truing tool eccentrically carried by saidrock shaft, an arm carried by said rock shaft, a rocker member, one ofsaid members having a slot and the other of said members having a rollerengaging in said slot, said roller and slot connection permitting axialmotion of said shaft while said rocker member is axially fixed, meansfor rocking said rocker member to rock said shaft, and means forcontrolling the axial position of said shaft while it is being rocked.

16. A wheel truing mechanism, comprising a rock shaft mounted forrocking and axial motion, a truing tool eccentrically carried by saidshaft, means for rocking said shaft, a lever fulcrumed transversely ofsaid shaft axis to be swung transversely of its fulcrum as said shaft isrocked, an abutment against which one end of said lever engages duringsuch rocking motion of said shaft, a cam member against which the otherend of saidlever operatively engages, and means for yieldingly holdingsaid shaft in the axial position for said lever to engage both saidabutment and said cam, whereby the contour of said cam determines theaxial position of said shaft as said shaft is being rocked.

17. A wheel truing mechanism comprising a rock shaft mounted for rockingand axial motion,

a truing tool eccentrically carried by said rock shaft, a rocker membermounted to rock on an axis non-parallel to the axis of said rock shaft,an arm mounted on said rock shaft, means for rocking said member, meansfor moving said shaft axially as it is rocked, and interengaging meansbetween said rocker member and arm for rocking said shaft as said rockermember is rocked for all axial positions of said shaft.

RALPH E. FLANDERS.

